That bill calls on the secretary of Transportation to make a new requirement for auto companies.

If it becomes a federal law, cars would need to have an alarm system that would detect a child's presence in the backseat. If the engine turns off and the child is still seated, the alarm would go off.

Mark Packo is a civil attorney and former engineer. He says car companies could be held liable if the alarms were ever to malfunction and for that reason he predicts resistance.

"[The car companies will say], 'If we are going to be mandated to do this, we also want some protection from the liability associated,'" Packo said.

Meantime, a bill in Florida calls for state law to change.

As it stands, the law has a time threshold - leaving a kid unattended for more than 15 minutes is illegal, but state Rep. Emily Slosberg, D-Fla. wants that to be "no minutes," meaning leaving a child unattended for any amount of time would be illegal.